The best treatment for kidney failure is usually a live donor kidney transplant (LDKT), which provides an average of 10 additional years of life compared to staying on chronic dialysis. Unfortunately, large racial/ethnic disparities persist in receipt of LDKTs. Blacks and Hispanics comprise over 58 percent of all dialysis patients but receive less than 28 percent of LDKTs. A little-studied and likely crucial cause of LDKT disparities is the lower likelihood that Black and Hispanic donor volunteers (persons interested in donating a live kidney) will complete the multi-step donor evaluation and actually donate. While minority donor volunteers are more likely to have medical contraindications to donation, they are also much more likely to discontinue the donor evaluation or decline participation in paired exchange (programs that permit LDKT using immunologically incompatible donor-recipient pairs). Based upon limited prior research, the outcomes of the donor evaluation may be especially affected by several potentially modifiable individual and health care system factors, such as donor volunteers' motivation to donate, health literacy, knowledge/education about donation, satisfaction with the patient care experience, and socioeconomic barriers to donation. These factors, however, have not been prospectively examined in a well-powered, multi-center, and diverse cohort of donor volunteers. The objective of this study is to determine how differences in modifiable individual and system factors are associated with Black and Hispanic donor volunteers' lower likelihood of actually donating. Our overall hypothesis is that donor volunteers who are Black or Hispanic are more likely to discontinue the donor evaluation, due to modifiable differences that either (1) are already present at the start of the evaluation, o (2) arise later in the evaluation process. To test this hypothesis, we propose a sequential mixed methods study. First, we will perform qualitative interviews of donor volunteers who previously discontinued their donor evaluations, to identify all the potentially modifiable causes of discontinuation of the donor evaluation (Aim 1). Then, in the quantitative component, we will perform a prospective cohort study of 2,800 live kidney donor volunteers at two large transplant centers in New Jersey and California. Among 575 Black, 875 Hispanic, and 1,350 White donor volunteers, we will determine differences in potentially modifiable factors that are present at the start of the donor evaluation (Aim 2) or arise during the evaluation (Aim 3), and also determine the impact of modifiable factors upon successful completion of the donor evaluation (Aim 4) and actual donation, directly or via paired exchange (Aim 5). At the end of this study, we will understand how Black, Hispanic, and White live donor volunteers differ in their potentially modifiable social, behavioral, and health services characteristics and how these factors impact both completion of the evaluation and actual donation. Our results, generalizable to the 230+ kidney transplant centers in the U.S., will enable us to design future interventions to improve the education, support, and care of live donor volunteers, to ultimately decrease racial/ethnic disparities in LDKT.